1. Field of the Invention
The present invention relates to a heavy vehicle ABS pneumatic brake system and, more particularly, the present invention relates to an improved valve seat for solenoid valve assemblies employed in modulators associated with pneumatic brake systems.
2. Discussion of the Art
Solenoid valve assemblies, and particularly the valve seats thereof, are of conventional structure in pneumatic brake systems. Typically the seats are made or formed of a bonded rubber. Rubber is desirable since it has good sealing qualities that conform to the valve member. That is, the elastomeric property of the rubber provides an air tight seal when the valve member engages the seat. This is one of the reasons that rubber seats are commonly used in pneumatic brake systems.
On the other hand, rubber or bonded rubber valve seats are relatively expensive. Also, due to compressibility of rubber, increased travel is needed to operate and seal a rubber valve seat. Moreover, they have durability issues. Temperature extremes result in different sealing capabilities of the valve seat. For example, when exposed to extremely cold temperatures, sealing performance of the valve decreases and is attributable at least in part to the valve seat. Accordingly, the inconsistency in performance, expense, and durability of bonded rubber valve seats have prompted consideration of alternative assemblies.
Thus, it would be desirable to provide a less expensive valve seat for a solenoid valve assembly used in a pneumatic brake system that overcomes the above-noted problems and others.